Washington’s Newest Area Code – 564, Soon Expanding

The phone numbers of some Washington State residents will soon be known by a newer three-digit area code.

Although it might come as a shock to some folks in The 509, the Evergreen State's original area code was actually 206, which not only covered Western Washington, but the entire state beginning in 1947.

Ten years later, in 1957, the 509 area code was introduced to divide residents in Eastern Washington in yet another way from their counterparts on the Westside.

These two area codes served the state for almost two decades until the introduction of the 360 area code in 1995, when the new three-digit number was installed for all residents west of the Cascade Mountains residing outside the Seattle Metropolitan area.

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In 1997, two additional area codes were added to the state's growing roster - 253 and 425, which were designed to serve the South Puget Sound and Snohomish County areas.

Although it might seem brand new to some, Washington's latest area code - 564, was actually introduced in August, 2017 for use in additional portions of the Southern Puget Sound region.

This week, however, the Washington Utilities and Transportation Commission (UTC) announced that newly-registered phone numbers within the existing 206 area code will be assigned as part of the 564 area code starting on June 10.

The move is part of the UTC's continuing effort to manage a limited supply of available phone numbers for the 206 area code, which is officially set to exhaust its supply before the end of this year.

Residents who receive the 564 area code will be required to use the recently-implemented 10-digit procedure for dialing all numbers in the state, including the applicable three-digit area code and prefix, plus the four-digit phone number.

The overlay of the 564 area code will not impact any existing numbers or prefixes assigned within the 206 area code, and will not change any rates for custom service with any carriers.

Washington State's current litany of area codes now stands at six, and UTC officials say a seventh will likely be added within the next five to 10 years to keep up with demand.

While Washington's list of area codes might seem to be bulging to many Evergreen State residents, it's well behind California's current roster of area codes which numbers 41 - the most in nation.

Meanwhile, there are eleven states that still only use a single area code, including Alaska, Delaware, Hawai'i, Maine, Montana, New Hampshire, North Dakota, Rhode Island, South Dakota, Vermont, and Wyoming.